The Ag ion-catalyzed ring-opening of a 1:4 mixt. of syn- and anti-cyclopropanes I and II gave the expected mixt. of CH2:CFC(OH)MeCMe3 and (Z)-MeC(CMe3):CFCH2OH in 56 and 19% yield, resp. Under similar conditions spiro analog. III underwent Wagner-Meerwein rearrangement to give bicycloheptane IV. Mechanism of the reactions are discussed. [on SciFinder (R)]